603
ACUS01 KWNS 130110
SWODY1
SPC AC 130108

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0808 PM CDT Sun May 12 2024

Valid 130100Z - 131200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
EASTERN TX INTO CENTRAL LOUISIANA AND SOUTHERN MISSISSIPPI...

...SUMMARY...
Large hail and locally damaging winds are possible from southeast
Texas into Louisiana and southwest Mississippi through tonight.
Isolated large hail will remain possible this evening across the
Edwards Plateau of Texas. Damaging winds and hail could still occur
this evening across northeast Wisconsin toward the Lower Peninsula
of Michigan.

...Synopsis...
A mid-level trough is currently traversing the southern Plains as a
second mid-level trough continues to graze the Great Lakes region
through this evening. A surface cold front continues to drift
southward across the northern Plains and into the central High
Plains, serving as a source of convergence for scattered strong
thunderstorms. Ahead of the surface front, a low-level jet will
become focused over eastern TX into LA and MS, supporting increased
lift and destabilization tonight due to warm-air advection. As such,
isentropic lift over convective outflow left behind by earlier
storms should encourage additional strong storms into tonight.

...Northern Plains...
Scattered thunderstorms continue to percolate in intensity over
portions of Wisconsin toward Lower Michigan. SBCAPE around 1000 J/kg
may support additional strong storms capable of wind and hail
(perhaps briefly reaching severe limits) for at least a few more
hours. However, nocturnal cooling should result in boundary-layer
stabilization, limiting the severe risk to very brief and isolated
occurrences.

...Central Plains into the southern High Plains...
Strong multicellular storms continue to develop along or near the
stationary portion of the surface front across KS into the TX/OK
Panhandles. Adequate low-level CAPE colocated with abundant
vertical-oriented surface vorticity has supported stronger cells
with a history of occasional severe hail and isolated landspouts.
The landspout risk should gradually diminish through the evening as
diurnal heating wanes and convective overturning from the many
ongoing storms reduces buoyancy. Given modest lapse rates over the
Plains though, at least an isolated severe wind/hail risk should
persist for at least a few more hours.

...Portions of central Texas...
An isolated supercell continues to progress south over Irion/Tom
Green Counties in central TX, and this storm may continue for a few
more hours given the presence of 7+ C/km mid-level lapse rates and
60+ kts of effective bulk shear. Deep-layer ascent should remain
weak through the remainder of the period, with convective coverage
expected to remain isolated. However, surface temperatures around 90
F amid low 70s F dewpoints, beneath 8 C/km mid-level lapse rates,
will support over 3000-4000 J/kg MLCAPE to linger over central and
southern TX through the evening. Furthermore, strong mid-level flow
overspreading this regime support elongated hodographs and 70 kts of
effective bulk shear. Should an additional storm develop and become
sustained, a supercell with large hail could result, warranting the
continuation and expansion of severe probabilities into the evening.


...Eastern Texas toward southern Mississippi...
Earlier storms have reinforced a surface baroclinic zone immediately
north of the Gulf coast, which will be overspread by a developing
low-level jet overnight. Warm-air advection atop this boundary will
foster over 2000 J/kg MLCAPE amid 70+ kts of effective bulk shear,
which may support multicells and transient supercells capable of
producing severe wind and hail through tonight.

..Squitieri.. 05/13/2024

$$